Lightning-arrester



(No Model.)

E. THOMSON. LIGHTNING ARRESTER. No. 401,085. Patented Apr. 9, 1889.

UNITED STATEs PATENT GEEICE.

llilllll THOMSON, OF LYNN, NASSACllllSl'll'iS.

LIGHTNING-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 401,085, dated April 9, 1889.

Application filed October 8, 1888. Serial No. 287,565. (No model.)

T0 all, 107mm, t may con/cern:

Be it known that l, ELIHU THOMsON, a citizen ot' the United States, and a resident of Lynn, in the county of Essex and State et Massachusetts, have invented acertain new and useful improvement in Electric-Arc Rupturing Devices and Lightning-Arresters for Electric Power, .Lighting Circuits, ttc., ot which the `following is a specification.

My invention relates to that class oi' electric devices designed to et'tcct the rupture of an electric arc 'formed between two electrodes or conducting-bodies by the direct application of some arc-disruptii'ig force-sucln for instance, as a magnetic held, a blast oi" gas or liquid, or any other directly-applied device adapted to displace or sever and put out the are. Such devices have been applied in connection with the plates or electrodes ot a lightniiig-arrester where there is liability to the formation and contiiiuance of an objectionable electric arc following upon the passage ot an electric discharge across the lightning-arrester electrodes. They are likewise applicable to the electrodes or abutments holding between them the fusible strip or wire ot an electric safety-'fuse when the fuse is used upon a high potential circuit or under conditions where the electro-motive force is suiiicicnt to maintain an electric arc between the electrodes or abutments after the fuse is melted. M invention is, however, applicable, not, only to an arc-rupturing device in connection with electrodes such as mentioned, but also to an arc-rupturing device applied to the are field between any two electrodes or conducting-bodies where it is desirable to elifect or assist in effecting the rupture ot' the are by a device acting upon the arc itself,

The object oi my present invention is, generally speaking, to increase the etlieiency and certainty ot' operation ot arc-rupturing devices such as l have described; and to this end my invention consists in the application ot a shield or septum ot insulating material between the opposed surtaces ot the arc-i upturing device and the electrodes or conducting-bodies between which the arc to be 'ruptured is formed, thereby preventing an are Afrom forming at any other portion et the electrodes or conductors than those directly subjectto the arc-ruptnring torce, and permitting the arc-rupturing device, when of conducting material, to be applied without danger of defective action very elosel y to the electrodes.

The protect-ing shield or septum may be of any desired material and applied ina variety of ways, either to theelectrodes or to the arc-rupturing devices, or to both, as may be desired. The arc-rupturing devices l have herein described tor the purpose of illustrating my invention consist ot' a magnet ap plied to the areing-eleetrodes after the manner described in my prior patent, No. SQlAtii, of July 7, i885.

Then my invention is applied to an arcrupturing device consisting ot' a magnet properly arranged with reference tttle'lectrodes across which the are to be ruptured is formed, the interposed insulating septum or shield maybe formed by coating or covering the poles or metallic portions of the magnet with enamel, rubber, or other insulating material, enamel being preferable on account ot' its incombustiblc nature. liy this means discharges or arcs which might otherwise pass vfrom the poles or electrodes placed in the magnetic ii eid to the magnet-pole, thereby escaping the action oi the magnetin rupturing the same, are prevented. l (ind it in tact desirable to apply the insulation-shield to all metal portions which are in proximity to the are to be ruptured, and also to coat or cover the electrodes themselves with insulating material at parts outside ol' the magnetic field, so that any` possibility of a discharge or arc Yforming at any other portion ot the conductors than those directly included in the magnet-ic field may be avoided.

ln the accompanying drawings, Figure l is a side elevation, and Fig. 2 is a vertical crosssection, on the line X, X, rig. '1, otl a device embodying my invention. Fig. shows in side elevation, and liig. i in plan, the application ol my invention to an arcruptnring dcvicc used with electrodes designed for another purpose. liig. 5 is a sect-ion, and Fig. (i a side elevation with a part broken away, of another i'orm ot my invention. AFig. 7 shows the application ci' the insulation to electrodes liable or subject to areing. Fig. .Q is a verti IOC) 'cal section, and Fig. 9 a horizontal section, of

a device constructed in accordance with my invention. Figs. l0 and ll are a side elevation and plan of a modified manner of mounting and constructing the arc-rupturing magnet and the arcing-electrodes. Fig. l2 illustrates another form of magnet applied as an arc-rupturing/d'evice. K

In- Figs.V 1 and 2, M M' are poles of a magnet, either a ermanent o an electro-magnet, between which are mountec t e electrodes E E', separated, as in the case of a lightningarrester, by a small interval or space over which a current of sufficiently high tension may force its way. As shown, the electrode E is connected with a line, L, while the electrode E' is either directly connected to earth or is carried to earth through the coils C C' of the magnet, of which M M are the poles. The electrodes E E' are preferably supported by insulating material, I I, and are also preferably coated with enamel or other insulating material, except at their ends, where they approach between the magnet-poles. The magnet-poles M M are, in addition, coated all over with insulating material or surrounded by caps of insulating material lying either close to the pole itself or separated therefrom by a small interval-it matters not which. Vhere the coils C C' are exposed to the action of an arc which might form between the electrodes E E', the coils themselves are coated all over with a layer of insulating material to a thickness, say, of one-sixteenth of an inch or less, protecting them from arcing or short-circuiting. It will thus be seen that-no metallic surfaces are exposed at or near the magnetic field except the electrodes E E' of the light- Y ning-arrester, similar to those described in my former patent referred to.

The connections of the deviceare unchanged in principle; but for relatively very high potentials the action is made very certain and is to be depended upon. Should a discharge occur to earth from the line L across the space between the electrodes E E', due to induction or static charge produced by lightning, an immediate formation of an arc may result, especially if the line L is grounded in like manner at some other point, and the-difference of potential of the grounded parts is high. Vhere the line L is one of heavy current and high potential, it is important to extinguish such an arc almost instantly, as it will create such a voluminous gas-stream as to do damage to the apparatus and be more difficult of extinction. The powerful magnetic field, however, in which the arc is formed when such magnet is properly magnetized results in a sudden break of suoli grounded current or arc. My present invention, on account of the layer of insulating material covering the poles of the magnet, allows such poles to be approached quite closely to the disrupting electrodes, thereby enhancing very much thc intensity of the field. This, in fact, is one of the important results obtained in my present invention.

My invention may with equal eeetiveness be applied to the case of electrodes normally having a fuse extending between them, as in Figs. 3 and 4, and placed in a circuit not grounded-that is, the magnet for disrupting the arc may, as I have indicated in other and former applications, be employed to surround a high-potential fuse, or a fuse in a high-potential circuit, or a circuit in which, after the fuse is melted by excess of current, the electro-motive force is still sufficient to maintain an arc in place of the fuse. As stated, the fuse is mounted between two supports, E E', as in Figs. 3 and 4, and, in addition, included between magnet-poles M M', which for continuous currents may be apermanent magnet or an electro-magnet traversed by a portion of the current, or an electromagnet in any circuit capable of magnetizing it; or, in the case of alternating currents, it may be magnetized alternately by a portion of the alternating current traversing the coils of the magnet. The magnet-poles M M' are in my invention coated, as in Figs. 1 and 2, with an insulating covering or shield placed close to the fuse F, and the supports themselves which uphold the fuse are, particularly where they pass outward or outside of the magnetic field between the poles M M', also protected or coated or covered with insulating material, so that an arc cannot pass from a point on one 'of the supports E outside of the magnetic field, and whatever arc forms or can form exists in the magnetic field between the poles M M and is disrupted vigorously by the action of the magnet. In fact, the moment the fuse softens the tendency of the magnet is to IOO rupture it by the magnetization of the current tending' to produce motion in the magnetic field, which in turn is enormously intensified the moment the arcis formed in place of the fuse.

In Figs. 5 and 6 the magnet-coil is a single coil, C, surrounding the bent portion of the horseshoe M M', and the whole structure, coil and magnet, is then inclosed in a complete covering of insulating material, which is shown at J surrounding the magnet on all sides and also the coil. The electrodes, one of which, E, is shown in Fig. 5, and both of. which, E E', are shown in Fig. 6, are presentedat a small distance apart between the magnet limbs or poles, and are preferably coated, as in Fig. '7, by an insulating covering, K K', in all positions or portions, except where they are presented to one another. This makes a simple device, and is applicable either to the electrodes, as shown, or to the electrodes or abutments holding a fuse.

In Figs. 8 and 9 is shown a slight modification, in which the electrodes pass through openings in magnet-poles, and therefore have no inside portions or extensions leading outward from between the poles, each electrode E E forming, as in the plan, Fig. O, a sort of bent piece inserted through the edge from the outside and separated between the poles vfrom its opposite electrode by a small spaee. ln this ease the electrode-pieces E E are ot course Carefully insulated from the magnetpoles where they pass through the same. This torni is particularly suitable where the magnet is a permanent magnet eoated all over with insulating material and carries thebinding-posts B B or eonneetions to the parts et the circuit, as in lfig. l., or otherwise.

ln Figs. lo and ll, Fig. lO being an elevation and Fig. lll a plan view of the electrodes, eopper pieees are set in or earried by the magnet-poles themselves, as shown, the poles being coated all over with vinsulating; material, as before; but the magnet-poles M M are not one piece ot' metal, but are two separate pieces kept apart by an insulating layer or septum at l, so as to virtually form an insulated horseshoe. They may be either permanent magnets or they may be provided with magnetizing-coils C wound thereon. In this ease one connection made to M, and the other from M is carried to ground, the eoil C being conveniently included in either circuit or ai'iywhere in the circuit where it is convenient to plaee it, and being covered u p from any possibility of contaet with heated gases or ares formed between the electrodes by a box er covering, as indicated in the ligure. The insulating-layer l, whieh may be a slip ot miea or slate, or even wood, is su'iiieient to insulate th e magnetie poles M M', which carry the eleetrodes E E and are in eonneetion therewith; but the magnetism is not so prevented from passing, and ean readily permeate the insulation l, and thus the strueture becomes in essenee ahorseshoe-magnet as before, whose north and south poles have between them electrodes E lil, but in this ease solidly attached to them and carried by the set of poles on their inner opposed faces. As before, the space between the pieces E E might be replaced by a tuse in cases where a tuse is required.

Fig. l2 shows the manner in whieh a simple eoil, C, might be used as a magnet to produce the magnetic field. In this ease the eoil is plaeed so that the plane of its winding i'ollows the position oi the magnet-pole and generates a lield in which the eleetrodes E E are mounted. To apply my present invention to this structure, the eleetrodes E E l would be coated except at their ends with insulating material, and the coil (l also be coated all over with a good heavy layer of insulator, or an insulating septum or shield ot solid insulating material would be interposed between the eoil itself and the disehargingelectrodes E E. The deviee,l7ig. l2, while useful, is not by any means as powerful in its actions ot' breaking an are between the electrodes E l as the electro-magnet devices which have been deseribed. lt is, in l'aet, an electro-magnet whose eore is simply an aireore without iron, and partalies, therefore, ot the properties et air-magnets in general.

Whatl claim as my invention isl. In an arc-rupturing device, a shield ot insulating material located between the surfaces of the electrodes and adjacent eondueting-'surl'aees et the device by which the arcis disrupted, as and for the purpose described.

An are-rulntn'ing device having its exposed surt'aees adjacent to surfaces o'l' the arcing eleetrodes or bodies shielded with insulating' material.

23. The eombination, with electrodes liable toV abnormal areing, otl an are-dispellingmagnet and a shield oi insulating material. between opposed suriaees oi the magnet and electrodes, as and tor the purpose deseribed.

i. ln an are-ruliituring device, a magnet whose poles are Covered with insulatingshields.

5. In an are-rul'ituring deviee,an intereeptin g-shield oi' solid insulator between the poles ot' an arc-rupturing magnet and the areingelectrodes.

o. ln an arc-rupturing deyiee, magnet portions shielded by an insulating-Covering, in Combination with shielded electrodes having anv exposed metal portion wholly within the space between the n'iagnet-poles.

7. ln an are-rupturin device, a divided magnet whose portions are electrically insulated, but free ior the passage of magnetism from one to the other, tl des of whiehmagnet eaeh bear one ot a pair ol ele 4'rodes eonneeted, respectively, to the parts an eleotrie circuit, substantially as described.

`Signed at Lynn, in the county et' fissex and State ot' Iiiassachusetts, this tth day ol' September, A. i888.

ELllIV '.IIIOMSON. Witnesses:

J. W. Gnaeounr, Guo. E. lCnnoNs.

IOO 

